FRACTURE-RESISTANCE BEHAVIOR OF MULTILAYERED SILICON-NITRIDE

This paper investigates the fracture resistance behavior of a novel si licon nitride with a unique laminated structure consisting of alternat e dense and porous layers, in the latter of which beta-silicon nitride whiskers were aligned parallel to the layer. The R-curve was determin ed by using a chevron-notched-beam technique when a crack propagated i n the direction normal to the whisker axis. The resistance markedly in creased whenever a crack passed the porous layer, resulting in stepwis e rising R-curve behavior. Microscopic study revealed that the aligned whiskers were almost completely pulled out in the porous layer.